Tobacco use among adolescents remains a major public health problem. Over the past 2-3 decades, considerable progress has been made in developing adolescent-oriented tobacco control programs. Several programs are now being offered via the Internet. However, many of these program fail to take full advantage of available modern technology such as interactivity, animations, video segments, video-game components, and other features that hold tremendous appeal for contemporary, computer-savvy youth. Our long-term goal is to develop adolescent-oriented tobacco control programs that are extremely successful in convincing young people to avoid using tobacco products or, if they are already using such products, to quit. Our recently completed NCI-funded study, "Teen Smoking Prevention and Cessation via CD-ROM" (Project ASPIRE), incorporated adolescent-friendly modern technology and demonstrated a significant beneficial impact, particularly in smoking prevention. The proposed project is a continuation of Project ASPIRE and will build on the strengths of Project ASPIRE and expand it in important ways. The new intervention, unlike its CD-ROM-based predecessor, will be Internet-based. While the original program was designed for and tested among inner-city, predominantly minority adolescents (6% whites), the new program will be targeted at a group of suburban and rural high school students with a substantially different ethnic make-up (approximately 50% whites) and socio-economic status characteristics. The original Project ASPIRE intervention will be substantially redesigned with careful consideration of the new target population and intervention setting. Because of the high prevalence of spit tobacco consumption among non-urban teenage tobacco users (35% according to our preliminary study), spit tobacco will also be addressed in the new program. Finally, in the new program, the classroom curriculum will be fortified with a strong, two-dimensional social support component: (1) virtual support at home via Internet bulletin boards and chat rooms and (2) human support via trained school personnel (teachers, coaches, counselors, and nurses). Our specific aims are to determine whether the new intervention results in (1) a reduction in smoking initiation, (2) an increase in smoking cessation, (3) a positive impact on spit tobacco use, (4) positive progression through the Transtheoretical model's stages of change in both smoking and spit tobacco use, and (5) positive change in key variables known to mediate tobacco use compared to a standard care condition. The study will be a group-randomized, controlled trial with 2000 participants aged 14-16 years from 16 high schools in suburban and rural southeast Texas. Follow-up assessments will be conducted at 6 weeks and at 6, 12, and 18 months.